WBC Disorder Lecture Notes PDF

HONG KONG METROPOLITAN UNIVERSITY MLS 3009SEF Haematology & Transfusion Science H.LEE WBC Disorder 10-2-2025 MLS 3009SEF WBC Disorder LEEYC 1  WBC Five main types of white blood cells, each with different...

HONG KONG METROPOLITAN UNIVERSITY MLS 3009SEF Haematology & Transfusion Science H.LEE WBC Disorder 10-2-2025 MLS 3009SEF WBC Disorder LEEYC 1  WBC Five main types of white blood cells, each with different functions. WBC differential count shows: The different types of WBCs are present in normal proportion to one another The numbers of the different cell types are normal, increased or decreased Abnormal and/or immature WBCs are present MLS 3009SEF WBC Disorder LEEYC 2  WBC Five main types of WBCs, neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Neutrophils normally make up the largest number of circulating WBCs. They move into an area of damaged or infected tissue, where they engulf and destroy bacteria or sometimes fungi. MLS 3009SEF WBC Disorder LEEYC 3  WBC Lymphocytes exist in both the blood and the lymphatic system and divided into three types, Separate specialized testing like immunophenotyping) must be done to differentiate the three types: – B lymphocytes (B cells) are produce antibodies that help protect against infections. Plasma cells are fully differentiated B-cells that produce antibodies, immune proteins that target and destroy bacteria, viruses and other "non-self" foreign antigens. MLS 3009SEF WBC Disorder LEEYC 4  WBC - T lymphocytes (T cells) finish maturing in the thymus and consist of a few different types. Some T cells help the body distinguish between "self" and "non-self" antigens. Others initiate and control the extent of an immune response, boosting it as needed and then slowing it as the condition resolves. Other types of T cells directly attack and neutralize virus-infected or cancerous cells. - Natural killer cells (NK cells) directly attack and kill abnormal cells such as cancer cells or those infected with a virus. MLS 3009SEF WBC Disorder LEEYC 5  WBC Monocytes similar to neutrophils, move to an area of infection and engulf and destroy bacteria. They are associated more often with long-term (chronic) rather than acute infections. They are also involved in tissue repair and other functions involving the immune system. Eosinophils respond to infections caused by parasites, play a role in allergic reactions (hypersensitivities), and control the extent of immune responses and inflammation. Basophils usually make up the fewest number of circulating WBCs and are thought to be involved in allergic reactions. MLS 3009SEF WBC Disorder LEEYC 6  WBC Disorder Leukocytosis – Total leukocyte count is more than 11.0 x 109/L in adult – Most commonly caused by increase in neutrophils Leukopenia – Decrease in leukocytes below 4.0 X 109/L – Most commonly caused by decrease in neutrophils MLS 3009SEF WBC Disorder LEEYC 7  WBC Disorder Neutrophil maturation-As the neutrophil matures: Size decreases Nucleoli disappear Chromatin condenses, indents, and finally segments The cytoplasm goes from an agranular, basophilic (blue) to a granular, more acidic (pink) color The order of maturation from committed stem cell to the mature neutrophil (also called a polymorphonuclear leukocyte or PMN cell): - Myeloblast - Promyelocyte - Myelocyte - Metamyelocyte - Band form - Neutrophil MLS 3009SEF WBC Disorder LEEYC 8  Myeloblast Myeloblast - high N:C ratio - fine chromatin - nucleolus - basophilic cytoplasm https://imagebank.hematology.org/ MLS 3009SEF WBC Disorder LEEYC 9  Promyelocyte Promyelocyte cells are a little bigger than Myeloblasts with - round or oval shaped nuclei, - Smooth/condense chromatin - N:C is more than 70 % - nucleoli are indistinct. - cytoplasm of basophilic staining primary granules www.MedSchool.com MLS 3009SEF WBC Disorder LEEYC 10  Myelocyte Myelocytes are typically smaller in size compared to Promyelocytes. - nuclei are round to oval - No nucleoli. - Coarser chromatin than in - cytoplasm of basohpilic staining with secondary/specific granules containing lactoferrin, histaminas, cathelicidins, lysozyme and collagenase, whereas, primary granules decreases. - N:C is more than 60 %. www,medical-lab.net MLS 3009SEF WBC Disorder LEEYC 11  Metamyelocytes Metamyelocytes are considerably smaller than myelocytes - kidney shaped nucleus (nuclear indentation) - partly dense chromatin. - pink cytoplasm with numerous secondary granules - N:C of more than 40 %. https://imagebank.hematology.org/ MLS 3009SEF WBC Disorder LEEYC 12  Band Form of Neutrophil Band –also known as a stab. - horseshoe shaped nucleus. - Normal peripheral blood may contain 1-10% bands (depends upon criteria for calling a cell a band): MLS 3009SEF WBC Disorder LEEYC 13  Neutrophil Absolute Neutrophil Count (ANC) 2.0 - 7.0 x 109/L Half of the peripheral neutrophils are freely circulating in the blood, the rest 50% are attached to the vessel walls (Marginating pool) There are two pools of neutrophils in the bone marrow: - Mitotic and capable of DNA synthesis (myeloblasts up to myelocytes –takes 3-6 days to mature to this stage) - Post-mitotic –serve as a storage pool of neutrophils (metamyelocytes up the mature segmented neutrophils –takes 5-7 days to mature to this stage) - These pools in the bone marrow represents 15-20 times the number of circulating neutrophils MLS 3009SEF WBC Disorder LEEYC 14  Function of Neutrophil During an inflammatory reaction, the body’s response with neutrophils enter the tissues where they are attracted by chemotactic stimuli released after tissue injury and during an inflammatory response. In the tissues, the neutrophils participate in phagocytosis (opsonization helps). Upon phagocytosis of the microorganism into a phagocytic vacuole, a plasma membrane bound oxidase is activated resulting in the formation of oxygen by-products that may be toxic to microorganisms (superoxide radical, hydrogen peroxide, etc.) Next primary and specific granules and secretory vesicles (collectively called lysosomes) fuse with the phagocytic vacuole, releasing their contents (degranulation). In this process most neutrophils die and are themselves phagocytosed by macrophages. MLS 3009SEF WBC Disorder LEEYC 15  Neutrophilia Absolute Neutrophil Count (ANC) > 7.0 x 109/L Occurs as a result of a reaction to a pathologic or physiologic process (reactive neutrophilia) Immediate – Increase lasts about 20-30 minutes – Redistribution of neutrophils from marginal pool to circulating pool – Neutrophils are mature – Seen in acute exercise, anxiety – “shift neutrophilia” or “pseudoneutrophilia” Acute – Occurs 4-5 hours post-pathologic stimulus (i.e bacterial infection) – Increase in flow of neutrophils from the bone marrow pool to the blood – Immature neutrophils numbers may increase Chronic – Follows acute neutrophila, if the stimulus continues beyond a few days – Storage pool in bone marrow depletes – Bone Marrow show increased numbers of early neutrophil precursors – “shift to the left”- increase in band neutrophils MLS 3009SEF WBC Disorder LEEYC 16  Neutrophilia 1. Bacterial Infection – Most common cause of neutrophilia – Seen with staphylocci and streptococci infections – Bone marrow increases output of storage neutrophils to peripheral blood, see shift to the left 2. Physiologic leukocytosis – No shift to the left – Birth to the first days of life – Childbirth – Extreme temperatures – Emotional stimuli 3. Tissue destruction/Injury, Metaboloic disorders – Neutrophil input is increased from the bone marrow to the tissue – Examples include: Rheumatoid arthritis, burns, gout, uremia, trauma MLS 3009SEF WBC Disorder LEEYC 17  Neutrophilia Leukoerythroblastic reaction – Presence of nRBCs – Shift to the left (increase in % of bands and even some metamyelocytes) – Poiki, tear drops, aniso – Associated with chronic neoplastic myeloproliferative conditions MLS 3009SEF WBC Disorder LEEYC 18  Neutrophilia Leukemoid reaction – Leukocytes> 50 x 10 9/L – Advanced degree of leukocytes in the blood that is not a result of leukemia – Transient; leaves when stimulus is removed – Many circulating immature leukocyte precursors seen – Seen in chronic infections, carcinoma of certain organ systems – Blood picture similar to chronic myelocytic leukemia(CML) Leukocyte Alkaline Phosphatase, is used to differentiate leukemoid reaction from CML LAP increased in leukemoid reaction, decreased in CML SCI 8003SEF WBC Disorder 2 LEEYC 19  Leukemoid reaction Leukaemoid reaction are often particularly marked in children. Granulocytes changes such as toxic granulation and Dohle bodies and a high neutrophil alkaline phosphatase score help to differentiate leukaemoid reaction from chronic myeloid leukaemia. The presence of a large proportion of myelocytes, a low neutrophil alkaline phosphatase score and the Philadelphia chromosome help to confirm CML. SCI 8003SEF WBC Disorder 2 LEEYC 20  Neutrophilia Leukocytes – > 50 x 10 9/L Shift to the left Presence of: – toxic granulation – DÖ hle bodies – cytoplasmic vacuolization – microorganisms SCI 8003SEF WBC Disorder 2 LEEYC 21 Morphological Changes of Neutrophils 1. Hypergranular neutrophils (neutrophils with toxic granules) These are neutrophils with coarse blue black or purple granules. Such granules are indicative of severe infection or other toxic conditions SCI 8003SEF WBC Disorder 2 LEEYC 22  Hypergranular neutrophils Dohle bodies are light gray-blue ovals found near the cell periphery composed of Rough endoplasmic reticulum which is RNA. Conditions associated with Dohle bodies, toxic granulation, and cytoplasmic vacuoles are infections, burns, cancer, toxic or inflammatory states. Toxic granulation are primary granules that appear larger and darker than they do in non-toxic states. Vacuolation Multiple clear vacuoles in the cytoplasm of neutrophils used in phagocytosis. Bacteria will look like small blue or basophilic rods or cocci (circles) inside the cytoplasm which indicate they are phagocytised organisms. Fungi are larger than bacteria but are also round or oval basophilic inclusions that can be phagocytized by the neutrophil SCI 8003SEF WBC Disorder 2 LEEYC 23  Neutrophil (Morphology) Inclusion Characteristic Composition Conditions Döhle body Light gray-blue oval near Rough endoplasmic Infections, burns, periphery reticulum (RNA) cancer, inflammatory states Toxic granules Large blue-black granules Primary granules Same as above (peroxidase) Cytoplasmic Clear, unstained circular area Open spaces from Same as above vacuole phagocytosis Bacteria Small basophilic rods or cocci Phagocytized Bacteremia or organisms sepsis Fungi Round or oval basophilic Phagocytized Fungal infections inclusions, larger than bacteria organisms SCI 8003SEF WBC Disorder 2 LEEYC 24 Neutrophil (Morhology) SCI 8003SEF WBC Disorder 2 LEEYC 25  Morphological Changes of Neutrophils 2. Hypersegmentation Neutrophils with more than six lobes to their nucleus (as many as ten or twelve may be seen) is an important diagnostic observation indicative of megaloblastic erythropoiesis (vitamin B12 and/or folic acid deficiency), iron deficiency anemia and uremia. MedSchool.com SCI 8003SEF WBC Disorder 2 LEEYC 26  Morphological Changes of Neutrophils 3. Pelger-Huet Pelger-Huet anomaly is an inherited dominant autosomal trait that results in neutrophil nuclei that do not segment beyond the two-lobed stage and may also appear round with NO segmentation. Pseudo-Pelger-Huet cells can be seen in myeloproliferative disorders or myelodysplastic states. Uptoday.com SCI 8003SEF WBC Disorder 2 LEEYC 27  Morphological Changes of Neutrophils 4. Pyknotic nuclei Pyknotic nuclei are degenerating nuclei found in dying neutrophils in blood or body fluid preparations. The nuclear chromatin condenses and the segments disappear, becoming smooth, dark-stained spheres. If the nucleus is round these necrotic cells may be confused with nucleated red cells jcp.bmi.com SCI 8003SEF WBC Disorder 2 LEEYC 28  Neutrophil (Morhology) Anomaly Description Conditions Pelger-Huët Neutrophil nucleus is bi- Can be real or pseudo lobed or has no lobes caused by drug ingestion May have a “pince-nez” or leukemia appearance clumped chromatin Hypersegmentation larger than normal Megaloblastic anemia neutrophils with 6 or more nuclear lobes. Pyknotic nucleus Degenerating nucleus Dying neutrophils SCI 8003SEF WBC Disorder 2 LEEYC 29 Morphological Changes of Neutrophils 5. Agranular Neutrophils Neutrophils devoid of granules and having a pale blue cytoplasm are features of leukemia SCI 8003SEF WBC Disorder 2 LEEYC 30  Neutropenia ANC 45% Self-limited Reactive process is due to infection or inflammatory conditions B and T cells involved Lymphocytes develop in response to antigenic stimulation. They become “activated” SCI 8003SEF WBC Disorder 2 LEEYC 45  Lymphocytosis Morphologically heterogeneous population presents signs of activation: – Large irregular shape – Cytoplasmic basophilia – Vacuoles Azurophilic granules can be present and are thought to contain pore-forming proteolytic enzymes and serine proteases with pro- apoptotic activity SCI 8003SEF WBC Disorder 2 LEEYC 46  Activated Lymph Normal Lymph Size 9-30 µm 8-12 µm N:C ratio Decreased High Cytoplasm Abundant Scant Colorless to dark blue Colorless to light blue Azurophilic granules Can scallop the RBCs Nucleus Elongated, irregular Round Chromatin Coarse to moderately Coarse fine Nucleoli Absent to distinct Absent SCI 8003SEF WBC Disorder 2 LEEYC 47  WBC SCI 8003SEF WBC Disorder 2 LEEYC 48 SCI 8003SEF WBC Disorder 2 LEEYC 49  Causes Infectious mononucleosis (IM) Toxoplasmosis Cytomegalovirus (CMV) Infection SCI 8003SEF WBC Disorder 2 LEEYC 50  Lymphocytopenia Defined as an absolute lymphocyte count of < 1.0 x 10 9/L Includes both inherited & acquired disorders Occurs due to decreased production or increased destruction of lymphocytes. SCI 8003SEF WBC Disorder 2 LEEYC 51  Immune deficiency disorder Impaired function of one or more of the components of the immune system: T, B, or NK lymphocytes – Decreased lymphocyte count=lymphocytopenia Body unable to mount an adaptive immune response Can be acquired or congenital SCI 8003SEF WBC Disorder 2 LEEYC 52  Acquired immune deficiency Acquired immune deficiency syndrome (AIDS) – Infection with a retrovirus, human immunodeficiency virus type-1 (HIV-1) – Transmission through sexual contact or contact with blood and/or blood products – Virus binds CD4 antigen on helper T lymphocytes which results in cell lysis SCI 8003SEF WBC Disorder 2 LEEYC 53  Eosinophil 1. Eosinophilia This is an increase eosinophil count above 0.4 x 109/ l and conditions associated with this include: allergic diseases (bronchial asthma, seasonal rhinitis), parasitic infections (trichinosis, taeniasis), skin disorders, chronic myelogenous leukemia 2. Eosinopenia This is a decrease in eosinophil count below 0.04 x109/l and conditions associated with this include: acute stress due to secretion of adrenal glucocorticoid and epinephrine, acute inflammatory states. SCI 8003SEF WBC Disorder 2 LEEYC 54  Basophil Basophilia This is an increase in basophil count above 0.1 x 109/l and is uncommon. It may associated with chronic myelogenous leukemia and polycythemia vera. Reactive basophil increases are sometimes seen in smallpox or chickenpox infection and in ulcerative colitis. SCI 8003SEF WBC Disorder 2 LEEYC 55 References A.V.HOFFBRAND & J.E.PETTIT: Essential Haematology. Blackwell Scientific Publications 3rd Edition. 10/2/2025 Henry Lee Haemoglobinopathies 56